From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753859AbXLKPZ0 (ORCPT ); Tue, 11 Dec 2007 10:25:26 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751671AbXLKPZP (ORCPT ); Tue, 11 Dec 2007 10:25:15 -0500 Received: from mail.tmr.com ([64.65.253.246]:47216 "EHLO gaimboi.tmr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751602AbXLKPZO (ORCPT ); Tue, 11 Dec 2007 10:25:14 -0500 Message-ID: <475EAFF9.9020405@tmr.com> Date: Tue, 11 Dec 2007 10:42:49 -0500 From: Bill Davidsen Organization: TMR Associates Inc, Schenectady NY User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.0.8) Gecko/20061105 SeaMonkey/1.0.6 MIME-Version: 1.0 To: Adrian Bunk CC: Marc Haber , linux-kernel@vger.kernel.org Subject: Re: Why does reading from /dev/urandom deplete entropy so much? References: <20071204114125.GA17310@torres.zugschlus.de> <20071204161811.GB15974@stusta.de> <47584E35.7030409@tmr.com> <20071208220345.GE20441@stusta.de> In-Reply-To: <20071208220345.GE20441@stusta.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Adrian Bunk wrote: > On Thu, Dec 06, 2007 at 02:32:05PM -0500, Bill Davidsen wrote: > >> ... >> Sounds like a local DoS attack point to me... >> > > As long as /dev/random is readable for all users there's no reason to > use /dev/urandom for a local DoS... > The original point was that urandom draws entropy from random, and that it is an an inobvious and unintentional drain on the entropy pool. At least that's how I read it. I certainly have programs which draw on urandom simply because it's a convenient source of meaningless data. I have several fewer since this discussion started, though, now that I have looked at the easy alternatives. -- Bill Davidsen "Woe unto the statesman who makes war without a reason that will still be valid when the war is over..." Otto von Bismark